-
Ha, I can see that...
The problem is it's probably 45cm back and the distance between top of the dishwasher and worktop is maybe <10cm? Certainly narrow enough that getting more than finger tip purchase on a screwdriver isn't possible.
Much cursing has been done - this is the only point it's attached to anything.
-
Mole grips on the expensed threads and unscrew as far as possible
Something like this to persuade the now protruding screw free
https://www.toolstation.com/roughneck-utility-bar/p52281
It's kind of hard to see what your problem is as you've been able to get such a good picture of the screw!
Is it a case where an angle adaptor would allow you to get on it or maybe the long Flexi head angle ones that go on drills.
I would be cursing whoever put that in.